The deadline to submit self-assessment tax returns for the year ended 5 April 2017 has past with a reported three million taxpayers failing to submit by the deadline according to HMRC.

Paul Haywood-Schiefer, personal tax assistant manager at accountants Blick Rothenberg, warned that for those who have missed the deadline, with no reasonable excuse, will be faced with a £100 late filing penalty, on top of any tax owed.

In addition to that, usually HMRC have 12 months from the date of submission to enquire into tax returns but where the return is submitted late, this is extended to the next “quarter day” whi...